SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a4033390f6b6b2ebdaf3c06f1eda3b11094ce254c7632c33e42f1636077e00b4' 
  AND token = 'MRCKWDAVlSmKLLel6UmTA/PCKNmCymj4FIXbwvRLHWc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}